Conflicting -i, -s, and -S use fixed precedence instead of the last case flag #197

Summary

tgrep resolves conflicting case flags using fixed precedence (-i above -s above -S) regardless of argument order. ripgrep uses the last case flag. This can either admit unwanted matches or silently omit expected matches.

This is separate from #183: the patterns themselves now participate in smart-case analysis, but conflicting flags still resolve incorrectly.

Reproduce

mkdir repro-case-order && cd repro-case-order
mkdir data
printf 'foo\nFOO\n' > data/a.txt

tgrep --no-index -I -i -s -- foo data
rg               -I -i -s -- foo data

tgrep --no-index -I -i -S -- FOO data
rg               -I -i -S -- FOO data

tgrep --no-index -I -s -S -- foo data
rg               -I -s -S -- foo data

# Passing control: the last flag is -i
tgrep --no-index -I -s -i -- foo data
rg               -I -s -i -- foo data

All commands exit 0.

The content-search cases reproduce with --no-index, an on-disk index, and tgrep serve --no-watch.

To repeat the indexed cases, run tgrep index data, remove --no-index, and keep the directory path data. For the server cases, start tgrep serve --no-watch data in another terminal and repeat those directory searches. --stats was used in the Windows harness to verify the selected backend, including (via server).

Environment

• tgrep 1.2.0, official Windows x86_64 release.
• Source inspected at release commit 3ba6ee02537281b68ee1366bb40df9f8b7cc54f0.
• Windows; test harness run with PowerShell 7.
• ripgrep 15.1.0 (af60c2de9d).
• Verified on 2026-10-12. The shell examples describe the same fixture bytes and arguments tested on Windows.

Cause

The three flags are independent global booleans in tgrep-cli/src/main.rs:54. tgrep-cli/src/search.rs:227 returns immediately for ignore-case, then case-sensitive, then smart-case, which fixes their precedence regardless of CLI order.

Possible fix

Resolve the most recent case flag before computing smart-case and constructing matchers or query plans. Preserve that resolution across explicit search subcommands as well.

A regression could cover all three failing sequences and the passing reverse-order control across the three search backends.